Project Summary In 2017, there were 19.6 million people living with HIV in eastern and southern Africa, of whom 56% were women. As the antiretroviral therapy scale-up continues and mortality declines, the number of older individuals with HIV infection is increasing. In Kenya, the proportion of persons living with HIV aged 50 or older is expected to increase from 13% in 2011 to 51% in 2040. Unfortunately, little attention has been paid to the needs of the rapidly growing population of older HIV-positive African women, who are disadvantaged relative to men economically, socially, and politically, and may face specific challenges with respect to ART adherence, persistent viral suppression, and overall health. This R21 application aims to determine the importance of social frailty in the overall health and well-being of Kenyan women aged 40 and over. Our work will address the following specific aims: (1) to characterize social frailty using a social vulnerability index (SVI) and a social network inventory among 300 Kenyan women aged 40 years and over, using stratified sampling to enroll equal numbers of HIV-positive and HIV-negative women with a range of ages; (2) to evaluate associations between SVI score category and both clinical frailty and disability in this population, testing whether HIV status modifies the association between SVI and either clinical frailty or disability; and (3) to explore associations between SVI score category and both viral suppression and ART adherence among the 150 participants living with HIV infection. Innovative aspects include a focus on an understudied, vulnerable population at high risk for adverse outcomes, adaptation of an existing SVI to the Kenyan context, comparison of social frailty and social network characteristics by HIV status, and examination of the relationship between social frailty and viral suppression, with use of hair antiretroviral levels to determine if viremia is due to treatment non-adherence. The highly productive research team assembled for this application includes Dr. Graham, an experienced clinical epidemiologist; Dr. McClelland, a women?s health researcher; Dr. Simoni, a sociobehavioral scientist; Dr. McCormick, an experienced geriatrician; and Dr. Mandaliya, a laboratory scientist and pathologist. This team is supported by the Medical Officer In-Charge for a large Comprehensive Care Clinic (Dr. Otieno) and the County Government (Dr. Abubakar) in Mombasa, Kenya and by an expert in social network research (Dr. Kennedy), an expert on antiretroviral level testing (Dr. Gandhi), and the CFAR Biometrics Core (Dr. Holte) in the US. This study will build on our team?s expertise and long experience with research on HIV and women?s health in Mombasa, Kenya. The proposed work will provide important insights into how social frailty impacts the health of older women living with and without HIV infection, and how interventions to reduce morbidity and promote healthy aging could best be targeted to meet women?s needs.